Apologies, it has been a while since I have looked into it.
http://www.odlmarkets.com/forex/
I have signed up and am using EA's / MT for putting on trades, I dont think it is classed as spread betting though.
Cheers,
Sebastian
Metatrader has a good Strategy Tester which can cover back to 90's (if I remember correctly), however the strategy would have to be written in the Metascripting language.
I use MT4 with ODL for FX.
Can write 'Expert Advisers' to automating trade execution / management and will use the same funds as is my general web based interface.
If I remember correctly, you would have to request it separately when opening the account though.